Microphone



R. H, MANSONI MICROPHONE.

APPLICATION FILED JUNE 23,19I7.

l 37%7Q8; Pautenteei May 17 1921.0

I'N VEN T04.

A T'ToRwE Y UNITED-STATES PA EN OFFICE.

BAY H. MANSON, OF ROCHESTER, NEW YORK, ASSIGNOR TO THE STROMBERG-CARL- COMPANY, OF ROCHESTER, NEW -YOBK, A.

SON TELEPHONE MANUFACTURING CORPORATION OF NEW YORK.

MICROPHONE Patented May 1'7, 1921.

Application filed June 23, 1917. Serial No. 176,512.

To allwhmnc'tmayconcem:

Be it known that I, RAY H. MANSON, a-

citizen of thelUni'ted States of America, residing at Rochester, in the county of Monroe and State of New York, have invented certain new and useful Improvements. in Microphones, of which-the following is a full, clear, concise, and exact description.

This invention relates to telephonic devices and more particularly to 'a micro-' phonic device-in which the resistance varying medium is comminuted material retained between two contact elements constituting walls of a containing chamber, one of the contact elements bein fixed and the other movable relative to t 4 e first. n

It relates particularly to providing in such a containing chamber for. the comminuted material an improved construction whereby the resistance to the movement of the movable electrode is reduced to a mlnimum, and the eifective area of this electrode having given resistance to movement is increased.

It is an object of my invention to rovide the means for accomplishing the a oresaid objects without causing defective operation of the instrument infother respects, such as packing of a portion of the granules of comminuted material which may be granulated 7 carbon.

Other objects of my' inventlon and the 1nvention itself'will be better understood from the description which follows. v I r The drawing shows a section of a telephonic microphone element so constructed as to constitute an embodiment of my invention. The drawing shows the telephonic element in section and in which 1 is the fixed carbon electrode, 2 is the movable carbon electrode, the fixed electrode being rigidly secured to the fixed shank 3 of the element which is adapted to be secured to the bridge of a telephone transmitter in any ofthe wellknown ways, and'the movable electrode 2 is secured by a metallic mount 4, stem 5, and

' clamping nuts 6 and 7 to a diaphragm 8, a

portion of which only is shown also in section. The comminuted granular carbon 9 Is also shown in the drawing between the ele c-" trodes 1 and 2. The main diaphragm8 W111 be constructed of some suitable material,

form of a disk has its'edge 12 beiveled so i that the face 17 of the electrode,12, is of larger area than the face 14 of the mount.

The carbon electrode 2 mounted on the beveled disk 4 is in the preferred embodiment illustrated, of the same diameter as the larger face 13 of the mount 4 to which it is is preferably of the same diameter as the smaller. face 14 of the mount 4. v

In prior constructions it has been usual to have the diameter of the movable electrode 2, both faces of the mount 12' and the clamping disk 11, of the same diameter. In my improved mlcrophone I depart from this custom and thereby attain .a highly improved result as will be later described.

Again referring to the-drawing constitutpreferablysecured. The clamping disk 11- ing a part of this specification, the periphcry of the mica sub-diaphra 10-is securely clamped by members 15 an 16, the member 15 also constituting a circular wall for the cup element. The shank 3 has an enlarged portion 18 constituting the outer wall of the cup, and to this outer wall is secured the member. 16 which in turn clamps themica sub-diaphragmlO, the member 15 and the electrode 1 securely together so as to make all of these the other. he mica sub-diaphragm 10 has a free portion'where' it maybe flexed by the forward and backward excursions of the electrode 2 under the controli'of the vibrating diaphragm '8 when the transmitterof which the diaphragm is a part is operated.

It can be easily seen that if a microphone were to be built having the members 4 and 11 of the same diameter as the movable elec. trode- 17, that this .free portion of the mica sub-diaphragm 10 would be considerably limited as itt-is limited with present con- 'StIl1CtlOI1S; and the resistance to fiexure thereof reatlyincreased. It is important to have t e electrode 2 of such a diameter as arts rigid with respect one 'to will provide a large area on its face-"17 to make contacts with the granules 9, and it is also very advantageous to decrease the resistance to flexure of the mica sub-diaphragm 10.

In the microphone of my invention I attain both of these advantageous results. It has previously been attempted to obtain the aforesaid results by a construction in which the mount member corresponding to 4 was cut away so that the face such as 14, was of smaller diameter than the face upon which the electrode rests as 13, but the advantage of my improved construction was not secured because the carbon granules wouldget between the enlarged ortion of the mount and the flexible sub-diaphragm restricting its free movement. In the microphone of my invention I prevent the granules from being secured between the mount and the sub-diaphragm by beveling the mount and giving the beveled edge a smooth surface.

What I claim is 1. In a microphone, the combination with a granular carbon containing cup, a cylindrica inner wall therefor, a carbon electrode disk for one of the end .walls thereof, a movable electrode, a disk mount for the said electrode having a beveled edge, the said beveled edge causing the-- said mount to have its faces of different diameters, and

a flexible diaphragm for the said microphone clamped to the smaller face of the said electrode mount, said flexible diaphragm with its carrying mount electrode disk forming the other end wall of the said containing cup.

2. In a telephone transmitter, the combination with a movable electrode and a fixed electrode arranged in a containing chamber having a cylindrical wall, granulated carbon in the said containing chamber arranged to contact with opposing faces of the said electrodes, a beveled edge for the movable electrode between its faces to cause one of the said faces to be of smaller diameter than the other, and a flexible wall for the said chamber to which the said movable electrode is clamped by its smaller face.

3: In a microphone, the combination with a containing chamber therefor having a cylindrical inner wall, a flexible diaphragm therefor, a movably mounted electrode secured thereto and adapted to be moved thereby, a quantity of comminuted resistance material adapted to contact with a face of the said mounted electrode, the other face being secured to the said flexible diaphragm, the said mounted electrode having its sides tapered, the first named face being larger than the second named face, and means to clamp the said flexible diaphragm over an end of the said chamber to close at one end of the said chamber.

4. In a microphone, the combination with garages a containing cup therefor having a cylindrical inner wall, a flexible diaphragm, an electrode adapted to be moved thereby, a

tapered mount for the said electrode to sesaid electrode to secure it. to the said flexible diaphragm, comminuted resistance material adapted to contact with another face of said electrode, the said mount constituting a frustum of a cone, the inside diameter of the containing cup being substantially greater than the diameter of the smaller end of the said mount, and means to secure the said smaller end of the said mount to the said flexible diaphragm, whereby the said mount may convey phonic vibrations (f)f the said diaphragm to the said electrode ace.

6. In a microphone, the combination with a containing cup, a movable electrode therefor, a disk mount for said electrode having a beveled edge, said beveled edge causing the said mount to have faces of different diameter, a flexible diaphragm for the said microphone clamped to the smaller face of the said electrode mount, the said flexible diaphragm, the said mount and the said electrode serving as an end wall of the said containing cup, another end wall and a substantially cylindrical. side wall for the said containing cup, the diameter of the said electrode being greater than the diameter of the smaller face of the said electrode mount, and being less than the diameter of the flexible portion of the said flexible diaphragm.

7 In a telephone transmitter, the combination with a main diaphragm, an auxiliary diaphragm rigidly connected thereto, a contaming chamber associated therewith, havmg parallel side walls, the said auxiliary diaphragm forming a flexible wall of the said containing chamber, a movable electrode, a mount and a clamping member therefor to secure the said electrode to the said auxiliary diaphragm, the said mount forming the frustum of a solid, comminuted material adapted to contact with the said movable electrode and a fixed electrode also adapted to contact with the said c0mminuted material whereby the oomminuted material is adapted to be compressed by movements of the diaphragm between the said electrodes.

8. In a microphone, the combination with a containing cup therefor having a cylindrical inner wall, a flexible diaphragm, a mounted electrode having a large and a small face, comminuted resistance material adapted to contact with the said large face, the said mounted electrode being secured to the said flexible diaphragm by the said smaller face, the edges of the mounted electrode being so shaped as to form the frustum of a cone.

9. In amicrophone, a casing provided with parallel inner Walls and having an open end, a flexible diaphragm clamped to said casing to form a closure therefor, an electrode, a beveled mount for said electrode located in said casing and secured to said diaphragm, a second electrode cooperating with the first, and comminuted resistance material engaging the opposing faces of said electrodes.

10. In a microphone, a casing open at one end and having an internal thread, a member threaded to engage the threaded portion of said casing, a diaphragm forming with said member a closure for said casing, a beveled mount carried by said diaphragm, means for causing said diaphragm to engage said member, two electrodes within said casing, one of which is secured to said beveled mount, and resistance material engaging said electrodes.

In Witness whereof, I hereunto subscribe my name this 22nd day of June, A. D. 1917.

RAY H. MANSON. 

